SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6578e7f59ef7a117d60a9a5cac6a76b8ec82eb966714eebc5a3adf9ab5bcb07d' 
  AND token = 'PzymT3cQgY64QhBbgy4xUdnaKq+S/+BCPujYgEf4NwA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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