SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '1d8ba99a1d39f969c7c4db944812c126053c8c59c03128815d6e5c23a2f57698' 
  AND token = '8KKp5BpOPQ9mYXqDNgItnKT4ms68CzJS+tVE3tc9M4g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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