SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66805aa1a380511664667630fb8e75a7f1c8eeb4beb6b0eb6135779211e40e7c' 
  AND token = 'i7lS8IhdvIb1JuF10v0wUfgIndxxcl5Wb+uj+EggYTo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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