SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f0ef561590ff961c2ed02f70d62fbc526237510db8ce68ea84a219693bea191' 
  AND token = 'Hc0KbPF+jYCco6FdnxFENMqNBvH+16WFsEMWxbVcWCk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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