SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a54349c6cfdabe0b862d5b20ec9d111ff9019ad66aac02ae26d90884c7a297c5' 
  AND token = 'z975+8o6qoQtqDgx4uAL+n3cUAGjazSv8UaF180Soqo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}