SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bc8e2bae0a95fe8a4acb474badd1e0dd61f0fcc3fdd7ca55b48bf0a8d8eb595' 
  AND token = 'AJAoUNOJz1UV3G7fyzEONewuZQz0I/2LiwMR6xfr4CU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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