SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb375c577bb1f99efde893ec52da691195a4ab2aff45a4ddb63683bb9dfcac9d' 
  AND token = 'HTq/mURuWNnayD7vZ3wfUo3SH3bCjRTsoY2abIsUznk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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