SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e8d5f2fc243e2bb4c817c7bc0bd2cd1f73198c05befe764123cda9f9b577b67' 
  AND token = 'rL5FAEMhF/BrG4iGbXT9gp1Le5m/vtwpAhhRO1NeibY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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