SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2b367b0e184dfa5b488ab012054a438309503281d7c5025bb3030de03ab3570' 
  AND token = 'D6tcpZdLjGSwlobQm06iVmGjLRVyUkwTusbAqbZ/x78=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00118

JSON explain

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