SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '64fba8983fd030f270c504753215fb4d5ecdcc23d0ff2302e4cab35197ea8856' 
  AND token = 'WIRbiKh0hIm5mtCzDdVzaUzmqm1YgRT2UTkoHt+6TI0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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