SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '565cbbce74c56b255581dc29e443a311043c792144f804373c459b0efa7a2278' 
  AND token = 'ZQuIpnFAo5Boida+Ofgf96RmRi1jGWVxhxY0otSnRyE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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