SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'cfa093b63df94dcdd830e4bc2619d57d9d4939fa8684b386688f2ae491d1abd8' 
  AND token = 'xu7M3g2ExLn84hFXG7tznvUyfw/cEjy6FgII7gvB+Ek=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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