SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e588923caca2b4c8bdba100c233f62865007d2e3bf76f7e44e0cf895afbc6a10' 
  AND token = 'mJ1kwpPLWUP5gvKRO8+Zqy4J/o/j1j01yAbqf+oSHDo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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