SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b4dbf8583e333f402eadef344d8363abe87a27f08118ee78ce827267e6c8506' 
  AND token = 'iyecXekJK2M4QfoBsdcTJZ5QxxVBWk12KrCmqRLcmF8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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