SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '963c6bb693c1b7414dbe19c3ca4ddc7a129b9d5d4c1d66de70344d6677063f15' 
  AND token = '2n80F5lv9vrEL7vQsueRGnEC5BU44mFic/FoIzwHJg0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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