SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f9bf468ef8ab86c7d1cbb42c786fa34efbe1c8e041c14bb17f361dcfe13b09c' 
  AND token = 'YyfffUgOxtHqbdk39gq1r3jN/v20CCHwtELrgoGrSEg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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