SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a624190e6219349d7934aaa7178c9015c289cdd70f94214b9e37f40b16755fd' 
  AND token = 'lHJ8RtcUWqwIdG4Xw5BUZBH0fc+rbjr/inAbBFal+m4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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