SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a68bbd85f8f66e312d3b6f16a55d08fcc02d47e2b1e488e9b918369c74d9c08' 
  AND token = 'cvaJ+XFYhp9Aad0vmB8DiPUxswVRBwhTLnlswkV83K4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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