SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc2a30aeccf1d5279a13c6e257c3925ff6cad778139f1d52d922533e7443c5b3' 
  AND token = 'w+qxH8R61zuavujR5ZUGijShhtvowkZAQWl2f+sGrUw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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