SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '686dcccf03523e6471373dcdd5699d03becd21898c16d1f5650ca1c660eba2cf' 
  AND token = 'li24qNpQdbALJGq54bRXwrteT7Zg3XCLemaZ6Vp/RIk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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