SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75aeb0a7de3cf6dcf67563346065cebf9d368491f8c485098f09e1539bfe2524' 
  AND token = 'Y7+sQ8SvVjMD5znR6WGaLi0XdGAtwquBktgIfIZzvgk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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