SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c984d8192ddb333d3b6062035293ba26e3dcc57237364de4b685219f226b1986' 
  AND token = 'RdmJ4jMmxoj+xUkOKV18C8akjLDroJHhfIbHuzO4qqg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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