SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e282173f269fb7fc5799f3f0d209910617c2351f84097af35d7965c8cfd789b' 
  AND token = 'KLHBZVzfUfJ7rqfRAzCahFjNwzB1ntARZs+atzr0fVk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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