SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6ba01d683adefc7ef434833e61a5027aaedfc5dde007d12b71990a8c4986920' 
  AND token = 'RzcCkCjSlkK7obQVfDgY/BXJTA4u/kTnZi9UOJEVwac=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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