SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a0e9e7774bcec10565b289fbb27729b63b8aa085d1edbaa7dee807625cca90a' 
  AND token = 'W/Ym1xkhfbNmrgSKbtwTZyPp2FgStykgVA5dcJAjSCM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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