SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '5a594f20d442ca53134b85578db9896492290ce70e65f4ff777037a57f42f335' 
  AND token = 'Qv/CXYdO/VDQLyWcgXrVkFQ//OhJ36fKmCcm3OSxSXI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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