SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f49a48a013a17ce0dcb4835ca09351fd91f01578b25b183e440a38b8ad978c16' 
  AND token = 'wLKqCJNECH0xofZPi/5Yal8F3Vpq6pzzZeO+yYgRqj8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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