SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3cf6c1cb5da4188d7d33fe7df35d55f8251ca061be836e1a03869e2178109fb8' 
  AND token = 'GblMPz7wA9gGHaxhPeyjWkNpNuvO66EnYVyweirao4g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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