SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d629ff601996820283989a5f709a0e2802fa432d0840cf9cc94f5df9a2a0945' 
  AND token = 'LPO0QKccElBt17nqcCDWVlPeXhkatmgiG5anuPCbspk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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