SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c219d8d5767eeae8dc4f0aff7d41d5a01f757b07051bf09db3d912fc5beace88' 
  AND token = 'Prj3FVOzREPTpsVCSAof7Hc1FKgRrnBcKm2n2qETYzI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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