SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '771772cc6ff307c4a4282cc3a76b96233801e1c1499deddd899832cdfa050971' 
  AND token = '/vFl+cE1jp3/Hjq4C0fUWG+6uyZImwimUC+ueAhFMpI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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