SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28759cfb2827a6727f2e8f76687803454d5ab3715d4fc6d63ec57b990663a1fc' 
  AND token = 'r7ogRRN7U2CnupYs0hG/HW+JEvu6X2yAMqHCmLwjgn8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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