SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4252b5ea437139ac9565db9e64b563698073f291bcbc2273cc538eae8148b7f9' 
  AND token = 'zgfa+Az2PqvV/D7u8lrIyNLM0+uTxW9PG/wApAcVBaE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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