SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3201973ca95ed2916dc2a906a7f8582c9f6594fdd8c1b21ef239daf6890f536' 
  AND token = 'vbsr6p2/NY+yhEc94bxV9gscueEDBXzzWhbjzvhqZng=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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