SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e830a402cf143cb3e26364dec213831d1946c715d8ceae0ad8bd13ebc1910f2' 
  AND token = 'F/Hhudrs7YsP+qVfBrgx/NiDb/73Fzy85DHQMPx2xMk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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