SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4eb29170cc3d57d31d2dba46501037380258f47310a062c79bf8de648f5e6f15' 
  AND token = 'jQCsPolDwwA5j6q0BMDjyRJTQMKhlBk/N5Vc1li+fhw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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