SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '866469bb6df54340924bdde0a607a5bc52d2e431d7efbd34389795111e08142b' 
  AND token = 'HCYOwhcT/bTJu141WFqyIlY8l71EDH5dysqq1Is0TLk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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