SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '401e515f8003e6f7ff1770b55d46b655d1c6ffb5823c78eeaaff86f80283352d' 
  AND token = 'KKdVrVy9S31y/c0UbWyyLP1bZyxiD7JNONQOsfx8Z7o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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