SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6debc0683f52729b0720450d8f511928bbeb280285f076b3b1b41d59ad871be3' 
  AND token = 'a5+9F9vi53pagaBye1Vfk/zyMxj3pxVIjxhv5xYLXvc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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