SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '996c6d73d6baa270647e0b70ebac1b2ae7e9f9fc5c88562de1e2ed8f64ba3933' 
  AND token = 'juP6BhDV9qgUBIyGZFNWgoADyG4jVIzI2Cyc9jDLnKE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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