SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3453ebd3e267af282375296dac170ce7e1b870f9911efdd5c6e314e8610c66b9' 
  AND token = 'vvp/u696/XWQxFLDH6KBxtLzptUgJ2mtLY9NC2JhE5Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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