SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '770564f68f242ca2c76efebebf8df07cb8357862f0c26032245273f058257bcc' 
  AND token = '8y7BsyBOT2w0b09gnq5oib5BJ3cHl20fJlWKQOq8RaQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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