SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9072b131c4c2fe9e6aa309afeba3273bd534bb94b00743d932bda6a4781a44d' 
  AND token = 'EmMD/JaXTjt26UNxc8bvlwvT9oUhAy2pYbs+s/wiB3Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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