SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2a597246c42cb4b0f4fd5d29ae4983b83f8700f6ef44dfd52d4d51578649727' 
  AND token = 'i0MlaG/HsPQDejvuGdzmxjnu+qlKyygSZWNxDalI8zk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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