SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4dc2b589e0b5139443f9eb4a644892f48afb062015a3d34ae70f4f3d94d121d7' 
  AND token = 'RDbj+cxQQMw2vawHg+nN/1vS7tp7LKw3qAPW5oWAMbo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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