SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0b05b5d094caca852d63389c7d0f883b21084e96f42d8d309cbac744c829ce5' 
  AND token = 'dNcvtxR3z7ZLPFiZLNtpVOEiPASuPenSgPzXvxvXOto=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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