SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '994f6794a0484f97d17441ecc5e2d36529692dd08c4834d03c23714425e977f0' 
  AND token = 'sEdSd0XmXYn2AQ2p3WoFw9KBbIcIErY0pbm2aJxR2jw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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