SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a11b78c6dc29a61e12a14825e7f82bb31e3420b57bc178b57fff90504f1a7887' 
  AND token = '8xyMruaEgQWLnjycOqOMJ2TuVtkonVqqbfrH1WQPQ1U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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