SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5bf90aed813d03891b8f82239bc4d971ba982e3a39eb3be2f31db1146b02815c' 
  AND token = 'UXWk2ggEJnYl2gWpz1DYjN9bKHCSgt5392K9u02tTWs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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