SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71a1c5a614cd581befcdc74f9eadb7946429f79660370b8562ef20dd7b88550c' 
  AND token = 'K365fVbeRh/pFpEji8lkvhtYPxrI2gqaCL6X40DFsAQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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