SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ea71b518204999c980bd527048eccc35a55cf90deebbd8885600a199d76261a4' 
  AND token = 'BF3xHbC17GBEk23kZlnud3Ue1eCP/s+jygFtHCS+irE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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