SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87a5ea7920ea925dd8128b40f21f9e715bb0fa6bfe0ed723d8eb9cd4bc8b5d91' 
  AND token = 'H4pTbRCJlFzomtcY6DchexMl6oaSaJIeQ9/LsUq34uU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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