SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c5675ddfd1c7204e254c6b751b19e4472178ce01bdb3b1299a44d82c25aeb2f' 
  AND token = 'wQGRUh4NHtwLgDv/vBIJV1lckgXAIViM35ITWk4jECY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}