SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '187b7b3668a90700974cf4dfe4f8492736d2d464d014a801564eb1e6018d5adb' 
  AND token = 'J9UJfLk/u255vuFUiqmcVFpv8OPjapQ3Xt1P5gEROj8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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