SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f6b66822022067d74b9401d65c841f9314af738fff22b12ead65a9bfe892ead' 
  AND token = 'dwc4+RntG9zjF/YXgKvWXzXNtiPrYMJ0sgOBLvn5Pd4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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