SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d836760961a2524b0a20e24540d1e8b5da148c447aaf96f8b8d5edaa3376047' 
  AND token = 'jSkeJ927Y3WlbJyhVX16ZUvjUxhwkcR5nJHY+GCHNqw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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