SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90ddbe368374dc5b2bb4b5ebf82926f11e7b5678385f0763665a578964dcd7ce' 
  AND token = 'mikdDEvfedqJqh6X2q5MzYtoISoy5RQoIeg27Qn48+o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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