SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b14c55845d82fb98df0abbbc2622fd11cef0b809082d3b9085067b8df7a31a3' 
  AND token = 't1U91bUjBXgn2j8oeTiL/zXHt290phZdkrq9lgHu63g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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