SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2879d63b0865bffa12923512ddfb1b79a4896d556e384acb35aa6e911f0c6dc' 
  AND token = '/G8aqSTvZqyJQU1PqyOGomibN0KG1ke8Y9JesBbSkTA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}