SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a354c537ecbf8613a19f3e89e9bc8b023c6bd198ce13bd66910177b29763b09' 
  AND token = 'wPble9pyLquedtC2YukhPJNrIYdOwpCjFKcPP4pjOBY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

JSON explain

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