SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84bc9a7bede7ce12ec0824b797563f9a2233079a7fc866934bff26973d314fc9' 
  AND token = '8phLh8PIhZ0Qsr4voq5NRB2bpejIDqvhnqCVxxw7Gck=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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