SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b6735f05fbd98de8b080326bbc6d12e5347b02a99885688dd7f8f67403e0e30' 
  AND token = 'qkhv2zMiJVHSePTMLkpvTomGMjYmORgZVzPZ3O8MeZc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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