SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf35e46db9d5d6f8b19e0277507d2e3778cdcd6876ac14f8aaf14c2171eb757a' 
  AND token = 'bCORTAuByzJejBmsIk772W0/sa/crCd8T7lZZMuRtvc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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