SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9560d068536b4ae3f8bee8f5c4f6cfe632d06b5c4c179725250e82f7460e58a' 
  AND token = 'AYJog+3B6kJJZtfiYwiSkL8UsxqeBHv/Sd+RAgIGfPk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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