SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd47c53916a321a8fa1e6ee9c1c74a6970f0eb5d0e5ff2d414a90679d571d96f0' 
  AND token = 'lW/Fhhk1tSRzVGkED6NegxVHOY1fjU/dCGQ6P/DVFWY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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