SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fafb1e8da69bfa2953663c54a4c79f5b25d0bf612e4fd3c51da4be4eb685ebea' 
  AND token = 'thZoTIipKwvTR3ulrl7f8wdDDsAuFpsJM03dGZYcukc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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