SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'ee52c90518c4f52cc896f590344b3cbbb6f3fb4aafebb2984ff502e17c26f8d5' 
  AND token = '7YgVuyqNlbKDwvZpWpi9iY4fHzK8i6LgruGFWmpGPQY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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