SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6158e67da7566afe343404421c86e9dd775d1ac1568d81ccccb00c27b3696198' 
  AND token = '7fnkQCF+yfu1Km90TkwglkZjMnXC0baLe56QvCr9do4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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