SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c8c5fb9bb0212893a1a04e6092841151e02d6312669c57971b656001405965f0' 
  AND token = 'UDIK/G+N4bzge/9MHqmA7LLl8rFO1pnYB6Ed+UAOoqo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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