SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5cf45537b7a56559b797cf879b6909da0c22d5a939913cb09083beda13d79288' 
  AND token = 'zL/XLZeQCnBn0Dg7Rfe95TxPTROTIb277Ziv13bNddk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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