SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '829e605a86048de0973d655ace6b66b33390c6da75c96ad4a4e8d28259c3e7a0' 
  AND token = 'wkJ9fDzHcH+epULlHxQfLhHMZcwiBwfDK/O3vktsnOM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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