SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f2494546b70caf32fc08df3bad66a6f059780be6a7339e4816bbdae35de5bac' 
  AND token = 'yKG0KEewuo/dVXXzFDXRlWfpAfBreIdGYY8+KhMtIjc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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