SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b45089c586e91a96888a188b5c76e72608ff974c0596e8de8dca5bc85080f9c3' 
  AND token = 'RbKH9yUvb7GaHIWO9rjltwzEtu60Id/ExPWxOi68OTU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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