SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7fd3f7479115cae3396014aabf039239f825cad0c5511adf4171f6dbcaac2d2' 
  AND token = 'ZmgkJ0EDFh2GAKnDt1nfwBb/eQnJ/gIflBa/U1uX6iE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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