SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a396e379916bd0b82e7cfcd7b699f76b556d3d6c48255f5ec41706546f0b967' 
  AND token = 'eX71PkVGWYnN0ODS5JxTIyU0SQY1MIvIvdyLREiqbTk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00008

JSON explain

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