SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c631dcf98222d44969e3e8ca7fbecba2405b89753a3590654f586c14f8c9941a' 
  AND token = 'eZWhdkdyqp2U3FHQFAE+CtZIGFod8B3fOvBSK+faJw4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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