SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44c6fc9021b1b878544b4e9cdeac97cd1360ffc0d4d2644b691825b77861ec6a' 
  AND token = 'xO11ILPzR/GfYTzhUhwlgK6GQh/DA/0ua9Ae/AXOZ58=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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