SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd74289de95fbfafc8acbcd2a00e567bb7f713496bc53ba0fa707e21d2fb19465' 
  AND token = '6rWevvvCKfIefVJ0Rt3nnW6cxAqIvI0vHzdEkCyhIHA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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