SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26e6dc1374e786da7d7a58bbe015e144cf309dd501ebcd5271833a52a1c1c6d7' 
  AND token = 'Ynca9f9FBe2SgorYwZaH9IYr9aqqEXLbvGDfMu1otiE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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