SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '417eb0a12149ee9d9344b612eb7f1010259b616d35aa59bda0572e7108a08ecc' 
  AND token = '9B3Tld30QUnhu602LHO2mE9Z3DxGKijtBLgy9UmSNsM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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