SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d3f6802e5b89a54f012a8e10bde8dfbd1b060a0c388510e2e2004414fc72fc5' 
  AND token = 'pyhIFwmL2wvoxtrrFEPMXiPt1Z1ZR8aPEmzVPC8pjck=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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