SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90f56c12fe293c2f16d5f304d730192a96f20105cb9e557e586268f759a180e8' 
  AND token = 'qjNh7tDcAFtdMG5BrdoRrLVgK41FQGgYIdGtjW1XxGs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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