SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3fbe3244b534fcad7505e7a3930d17a379bcfabcdbd5887facc7ede1cb5e7bc' 
  AND token = 'zDXf5J0ZeeMoSnovGGpkE2GlDW+hnkUclUVHflCRAA0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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