SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1759b3f6bb877fb49b6420aef32c83723e82ec976a58e6e507b8a78fb1507326' 
  AND token = 'BcGJyNqsMhkypLPl/Q7ysBqmRCz2cZ90fGsFMgz+7gc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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