SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4df70022c7c6f0d5ea45c94e25ff2981322502e9bfb6c44c1fd776244559a238' 
  AND token = '3LsbVymTYB+pPvbqNUxDXuKdHBizo7Ne8U+MI1zKIMs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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