SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b76661127fa477a024a9178b07c1f5bd3fb27fcc87c95750d0d5d0812748f12f' 
  AND token = 'zJbhCxrCycl0uwJuqVompVAHp8OO/Gx5rKzZuyWY504=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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