SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'e8f6502cb8f16b70957208e2c7abeab00284c22fab850de1d090a587e73d1536' 
  AND token = 'FaiZk4LpcwP6Fu9ez0G0RUAbQCRWtMhY2XT2ZGGxm1k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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