SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '247e7c5416116f2a695a06481901ca933ff9fb0032f251fade7adaa8426f3929' 
  AND token = 'I/6YoM6YGcz6NFHIImUwHnbf2jNr3Gf5ZDJuJDteaK0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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