SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e134a47f882330c4753b4fab8237ffdad0c41be2483e19fa77af02b52dae0e9' 
  AND token = '0Q0Fp2r7o8AUMalkQIEkg+50mzTfLQZlFr/DvxklmN4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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