SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df61ffbd5d906193cf5d68b4b4f8a28aeae7d1a3a97560a78755b8d986f55ff5' 
  AND token = 'zv20AXd1Y8z1q4J2vlEEQazxKfFM8wiDxXNtBPIiO4A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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