SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9fdbdf94d210581e3fa9e20dd9657549dc9bfa8c4ae505e073bd439272255aee' 
  AND token = '+Mkw79uIyWmFUaUD+RmUGsEMw6tbtCmvq0NTloqKrm8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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