SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '39c73fd21ea1cf41089cd00d1498f0728ccc6c025951631170adedb1be212fc3' 
  AND token = 'dp7nSnV2y76V/YGj5BE0AsVyw4AYblSTyqGHvWkPawA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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