SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '79a8aed23a7fb7df671f2790db7945d18c0802d5ff052653acb7a53a470c344a' 
  AND token = 'R12+NvGCc47XajO25xqt6DguSkAjTghpAO/rMCrVtXo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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