SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b03928e57656f26528c41f7c31ba35f6893cdff44bfbbbfc720e976caf1c7cc0' 
  AND token = 'k/eiccqgwe0mwoJ4unR3nAUOzQ+2FrRKsfboaAjvVyc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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