SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e8938e2cc9adbf9d80337a41f71a9a93715f5006f9d1da7996a21f031c756ce1' 
  AND token = '+yxAas95sYdTBSBthvdRRzV/jOX7lxOK/C6ntN88gjk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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