SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f469eb1f085e3f8704c80ecfcf8e987395329de8980e0670edd471d0ef61c9db' 
  AND token = 'fF2afMS9Jv+3LJtJmIBXL/UgtKIgPiatrP0tqMv0fb4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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